Home AV setup help needed

I bought a mac mini a few months ago as I wanted to digitise my DVD collection.

Since then we have become a bit of a Mac household, buying a number of products, most recently the Ipad (still to be delivered).

What I would like to achieve is streaming video/music/photo's around the house and remotely controlling the mini mac.

At the moment I have the mini in the front room connected to the TV, playing films fine. I can stream Itunes to remote speakers upstairs through the airport extreme. And can control itunes with my iphone.

What I haven't yet managed to do is stream films & pictures around the house and to the projector in the movie room.

Will the Ipad allow me to do this or do I need to buy more kit? I was considering adding apple TV but not sure this is the best way to go. With the Ipad on order I want to make as much use of that as possible.